A composite electronic component of interest to the present disclosure is disclosed, for example, in Japanese Unexamined Patent Application Publication No. 2011-181512. The composite electronic component disclosed in Japanese Unexamined Patent Application Publication No. 2011-181512 includes a component body having a laminated structure composed of a plurality of laminated insulating layers, and a coil portion providing a common mode choke coil and a protection element portion providing an electro-static discharge (ESD) protection element are disposed so as to be aligned in the lamination direction of the component body. The ESD protection element has a structure in which a gap is formed between paired electrodes and static electricity is released via the gap to ground.
FIG. 10 shows a preferred equivalent circuit of the composite electronic component disclosed in Japanese Unexamined Patent Application Publication No. 2011-181512.
Referring to FIG. 10, the composite electronic component 1 includes: first and second coil conductors 3 and 4 that form a common mode choke coil 2 and are magnetically coupled to each other; and four ESD protection elements 5 to 8.
One end of the first coil conductor 3 is electrically connected to a first coil terminal 9, and one end of the second coil conductor 4 is electrically connected to a second coil terminal 10. The other end of the first coil conductor 3 is electrically connected to a third coil terminal 11, and the other end of the second coil conductor 4 is electrically connected to a fourth coil terminal 12.
One end of each of the first to fourth ESD protection elements 5 to 8 is electrically connected in common to a ground terminal 13 to which a ground potential is applied. The other ends of the respective first to fourth ESD protection elements 5 to 8 is electrically connected to the first to fourth coil terminals 9 to 12, respectively.
Such a composite electronic component 1 is mounted on a pair of signal lines such that, for example, signals are inputted to the first and second coil terminals 9 and 10, and signals are outputted from the third and fourth coil terminals 11 and 12. The ESD protection elements 5 to 8 are able to absorb an overvoltage caused by electro-static discharge, and thus the composite electronic component 1 functions as a common mode filter having an ESD protection function.
In recent years, achievement of high speed and high capacity for signals, and multi band has been accelerated more than ever in an electronic device typified by a cellular phone. As a result, generated signal noise has had a wider band and a higher level. Therefore, for example, for the composite electronic component 1 disclosed in Japanese Unexamined Patent Application Publication No. 2011-181512, there has been a concern about whether the composite electronic component 1 is able to sufficiently remove signal noise having a wide band and a high level as described above. Accordingly, there has been a demand for an electronic component that is able to achieve a higher-attenuation and wider-band noise removal effect.